Benthic Estuarine Assemblages of the Northeastern Brazil Marine Ecoregion

Abstract

The estuaries of the Northeastern Brazil Ecoregion are dominated by mangrove ecosystems and tend to present high salinity values due to elevated temperatures and low rainfall. Nevertheless, they present a high photosynthetic productivity as a result of continental nutrient input and intense insolation. Those singular environmental conditions (shallow estuaries) are reflected in the composition and structure of marine invertebrate assemblages and consequently in the way in which these organisms interact with the environment. Although there is reasonable knowledge about benthic biodiversity from estuaries of the Northeastern Marine ecoregion, ecological knowledge on benthic assemblages, including their spatial and temporal dynamics, is scarce and mostly restricted to a few estuaries. However, general estuarine gradients such as an increase in benthic species richness towards euhaline sectors are observed. Species richness and macrofaunal abundance are higher during dry seasons. Benthic assemblage zonation is observed in unconsolidated bottoms along the intertidal zone, with mangrove trees being colonized by their own set of organisms. Estuarine areas in this ecoregion are being greatly impacted by economic activities, with shrimp farming advancing fast in some areas. Thus, environmental education will be of great relevance towards a sustainable use of ecosystem goods in the Northeastern States in Brazil.